1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "LocalArray.h" 18 #include "readlink.h" 19 20 #include <string> 21 #include <unistd.h> 22 23 bool readlink(const char* path, std::string& result) { 24 // We can't know how big a buffer readlink(2) will need, so we need to 25 // loop until it says "that fit". 26 size_t bufSize = 512; 27 while (true) { 28 LocalArray<512> buf(bufSize); 29 ssize_t len = readlink(path, &buf[0], buf.size()); 30 if (len == -1) { 31 // An error occurred. 32 return false; 33 } 34 if (static_cast<size_t>(len) < buf.size()) { 35 // The buffer was big enough. 36 result.assign(&buf[0], len); 37 return true; 38 } 39 // Try again with a bigger buffer. 40 bufSize *= 2; 41 } 42 } 43
